Clean and Maintain Your Furnace

Level: Experienced

Once a year you should take some time to perform a checkup on your natural gas furnace. Routine maintenance and cleaning will help you ward off the cold, keep heating bills low and make your home more energy efficient. You can also save money by doing the annual furnace maintenance and tune-up yourself and foregoing a potentially pricey call to a professional.

Step 1: Turn Off Power and Gas

Once a year you should take some time to perform a checkup on your natural gas furnace. Routine maintenance and cleaning will help you ward off the cold, keep heating bills low and make your home more energy efficient. You can also save money by doing the annual furnace maintenance and tune-up yourself and foregoing a potentially pricey call to a professional.

Safety Alert!

If you're not sure about how to properly turn off the electricity or gas to your furnace, or are unsure about how to go about the maintenance, consult a professional HVAC technician who can safely maintain and clean your furnace for you.

Step 2: Clean Inside/Maintain Parts

Open all access panels and use a wet/dry vacuum to clean out dust, dirt and debris from around the motor and blower, inside the burner compartment, and from other mechanical parts. Use the vacuum's brush attachment for fan blades and general debris removal; use the crevice tool to get to hard-to-reach areas. Be careful not to jostle or disconnect wires when you're cleaning inside compartments with the vacuum and brushes.

After vacuuming, use a slightly damp cloth and wipe everything down.

Inspect all wires and connections. Use a screwdriver to tighten any loose terminals.

Apply heavy-duty electric motor oil to the fan shaft and motor if there are oiling ports. Be careful not to over-oil your furnace and never use automotive motor oil or 3-in-1 household oil. Check the motor's belt to see if it is loose or cracking. If you see cracks, replace it. Take the belt to your local True Value hardware store to find an exact match. If the belt seems too loose, tighten it down by first loosening the attachment bracket, then pull the belt until it's tight and retighten the bracket. Clean the thermocouple with a cloth. Use a precision duster with compressed air to clean in and around the pilot light.

Helpful Tip

An old toothbrush or other small-sized brush can help you remove any stubborn dust and debris from fans and other parts. Toothpicks or cotton swabs are good for getting into very small openings on machinery such as the blower.

Safety Alerts!

When cleaning with compressed air, always wear protective goggles and a dust mask.

When gas lines need repair or replacement, call a professional technician for help unless you're absolutely sure you know how to perform this maintenance correctly.

Step 3: Clean/Repair Furnace Ducts

Clean ducts thoroughly using a high-powered vacuum cleaner with a HEPA filter. The HEPA filter will prevent large amounts of dust from scattering throughout your house. If your home has a forced-air furnace, vacuum ducts regularly. For a furnace with a built-in humidifier, clean the humidifier with a de-scaler to make sure it continues to works properly.

Patch any leaks in your ductwork to make your heating system more efficient. Leaky ducts allow warm air to escape and make it harder on your furnace to do its job. For small holes, you can use good old-fashioned duct tape to seal it up. Any hole or tear larger than 3" or 4" should be repaired with a sheet-metal patch. Cut a piece to fit and fasten with drilled-in screws or fasteners.

Depending on the damage, ductwork may need to be replaced altogether. To seal joints, first wipe dust, oily film and grease from the ducts with a clean cloth. Apply foam sealant at least 1" on each side of the joint, using a 1" natural-bristle paintbrush. When this has set, wrap ducts with pipe insulation.

Use a large scrub brush to clean the exteriors of all vents and registers around your home. Remove the vent cover with a screwdriver and clean the inside using the high-powered vacuum cleaner with a HEPA filter. Replace the vent covers when done.

Step 4: Replace or Clean Furnace Filters

Models vary, but there will be access panels that you must open or remove to get to your furnace's filter (Keep a screwdriver handy — you may need to loosen screws to open a panel). Replace any disposable filters with new ones. If you have washable filters, remove them from the furnace and clean them with mild detergent and water. Let them dry completely before putting them back in.

Helpful Tips

It's best to buy high-quality filters. While good ones may be a little more expensive, they will take out more pollen, dust and other irritating air particles than the cheaper filters. The trade-off is the high quality filters must be changed every three months because a dirty filter will make your furnace work harder, and waste energy.

Consider using high-efficiency pleated air filters. These filters allow your furnace to pump cleaner air into your home. The pleated design increases the filter's surface area, capturing more lint, dust, pollen, mold and mildew. Also, pleated filters don't need to be replaced as often as standard filters. Pleated filters should be replaced every three months compared to every month for regular filters.

Check your filters monthly and replace them when needed throughout the year.

Step 5: Run/Test the Furnace

After you have cleaned and made any repairs, close all access panels and restore power and/or gas to the unit. Allow the furnace to run for several minutes while listening for any noise that doesn't sound right. Also be attentive for any unusual smells, such as burning. If something doesn't seem right, shut it down and investigate. When in doubt, call in a professional.

Helpful Tips

Your furnace burners should be projecting blue flames. If the flames are yellow, they are high in oxygen content and need to be adjusted or serviced. If you're not sure how to fix this, call a professional.

Use a programmable thermostat to control your heating and cooling system so that it runs more efficiently and saves you money.

That's it! Your furnace should now be fine-tuned and ready to fight the winter cold.

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